atrociously
barbarously
bec et ongles
bestially
brutally
brutishly
cruelly
devilishly
diabolically
ferally
fiendishly
fiercely
inhumanely
inhumanly
mercilessly
pitilessly
ruthlessly
savagely
sharkishly
slaveringly
tooth and nail
truculently
unhumanly
viciously
wolfishly